"Select multiple emails and export them to open with Excel."

@archi

could you please shade some light on what you are trying to accomplish? 

To export multiple emails for use in Excel, first select the emails in your email client (like Thunderbird or Outlook). In Thunderbird, you can use the ImportExportTools NG add-on to export emails as a CSV or HTML file. In Outlook, go to File > Open & Export > Import/Export, choose Export to a file, then select CSV or Excel. After exporting, simply open the CSV or HTML file in Excel, and you’ll be able to work with the email data like any spreadsheet.